Cylinder head for internal-combustion engines



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led March 37 A FRANCHETTI CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Nov. 23 1926.

Patented Nov. 23, 1926.

UNITED STATES ALESSANDRO ERANGHETTI, CF FLORENCE, ITALY.

CYLINDER HEAD FOR INTERNAL-COMBUSTION ENGINES.

Application filed'March 27, 1925, Serial The present invention relates to cylinder heads of internal combustion engines, and the invention is applied more particularly to those four stroke internal combustion engines having the two principal valves on a common axis and set at right angles to the axis of the cylinder.

The cylinder-head part exposed to high pressures and temperatures and designed to resist the same is, according to this invention reduced to a very simple form and of limited dimensions, to permit its construction with suitable material but avoiding excessive cost. The other parts may on the contrary be big and of ordinary material.

An embodiment of this invention is shown in the accompanying drawings, in which- Figure 1 shows a sectional view of the head along the axis of the cylinder.

Figure 2 is a front view.

Figure 3 is an exterior view of the inner part of the cylinder head and Figure 4 is a front View of the cylinder head itself.

Referring especially to Figure 1 a represents the extremity of the working cylinder to which the head is fastened by bolts b.

The inner part of the cylinder head or combustion chamber is shown by c-.

A large flange piece d serves to fix said cylinder head or chamber and to complete the water space -e-.

The piece c also represented in Figure 4 comprises an inner wall -g rather thin to facilitate the transmission of heat, and an outer wall f of substantial thickness, able to resist the stress which it receives from the inner wall -f insuflicient in itself to resist the inner pressures.

Between the two walls fg the cooling water circulates, the chamber of which is completed by the flange piece 0Z-.

The wall g (see Fig. 3) has only four openings, one of which communicates with the cylinder a; two in which are placed the exhaust and admission valves; and a fourth in which is placed the piece -h where the fuel injecting valve and the starting valve are attached and through which any other necessary passage etc. may extend.

Thus the openings in the combustion cham ber are reduced to a minimum, diminishing the possibility of cracks which as is well known begin just in the proximity of the said openings.

No. 18,702, and in Italy April 10, 1924.

The outer wall f is flared outwardly towards the end opposite to the cylinder, as much as is allowed by the studs connecting with the cylinder, thus producing a very large opening in the water-j acket that allows of its thorough inspection and cleaning.

The flange -cl that closes said opening can be immediately removed, without touching the main valves of the engine, thus immediately exposing to view nearly the whole of the inner wall.

The shape .and strong thickness of the outer jacket g has also the effect of compensating the tension caused in the inner walls, during the cooling of the casting, when moulded, from the fact that the outer walls if of the same thickness, become solid sooner than the inner ones.

By making the outer wall of approximatively double thickness in spite of being more subject to cooling, it will remain liquid until the inner wall is solidified and then in the further cooling it will be shrunk against the latter and give to it a compression or negative tension that will balance the tension due to the working pressure of the cylinder.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a hollow water cooled cylinder head casting for a four-cycle internal combustion engine, comprising inner and outer walls, the outer wall flaring outwardly from the cylinder end of the engine, said casting having four openings therein to accommodate respectively the cylinder, the inlet valve, and the exhaust valve of the engine and an end cover plate, the said cover plate being held against said casting, and the latter against the cylinder, by means of a plurality of stud bolts.

2. In a hollow water cooled cylinder head casting for a four-cycle internal combustion engine, comprising inner and outer walls,

the outer wall being conular in form and being substantially thicker than the inner wall andflaring outwardly from the cylinder end of the engine, said casting having four openings therein to accommodate re spectively the cylinder, the inlet valve, and the exhaust valve of the engine and a flanged end cover plate, the said cover plate being held against said casting, and the latter against the cylinder, by means of a plurali ty at stud bolts.

3. In a hollow Water cooled cylinder head casting for a four-cycle internal combustion engine, comprising inner and outer Walls, the outer Wall being conular in form and thicker than the inner Wall and flaring outwardly from the cylinder end of the engine, said casting having four openings therein to accommodate respectively the cylinder, the inlet valve, and the exhaust valve of the engine and a flanged end cover plate, the said cover plate being held against said casting and the latter against the engine cylinder by means of a plurality of stud bolts passing through said cover plate but spaced out-- Wardly from said casting and embedded in the engine cylinder firmly compressing and vedging said casting between the engine cylinder and said cover plate.

4. A Water-jacketed cylinder head for a four-stroke internal combustion engine comprising an inner Wall enclosing the combustion chamber, an outer Wall of approximately conical shape, the small end of the cone being connected with the inner wall, and the large end of the cone forming a very broad opening through which all parts of the inner Wall can be reached, inspected and cleaned, and a flange adapted to close said opening and complete the Water-jacket.

ALESSANDRO FRANCHETTI. 

